1. Field of The Invention
The present invention relates to a single-piece seal member for forming a secondary seal around a base structure, such as a shower, sink, bathtub or similar basin. Particularly, the present invention is directed to a single-piece seal having a substantially rigid portion and a substantially flexible portion, wherein the substantially rigid portion includes a mechanism to engage a surface of the base structure with the substantially flexible portion arranged in an upright manner.
Further, the present invention is directed to a method of forming a secondary seal around the base structure using the single-piece seal member.
2. Description of Related Art
Water containment is an important consideration during the construction and installation of sinks, bathtubs, shower stalls and similar basins. Bathtubs and shower stalls in particular are continually exposed to large amounts of water. Tubs and stalls require special consideration as to their design, construction, and installation so as to contain water and prevent water from leaking into the surrounding wall structure.
If water permeates beyond the tub or stall, the water will likely contact the surrounding wood framing and insulation. The wood framing and insulation typically are not exposed to enough air or air circulation to dry out once they become wet. Consequently, the water may cause rotting and other deterioration. Such deterioration leads to structural instability and foul odors. In sufficient quantities, water, following a path of least resistance, could leak into other areas of the dwelling.
Once the integrity of the wood framing and insulation are lost, it is difficult to replace or repair. Repair work could require the removal of surrounding tile, or the entire tub or shower unit if the tub or shower is a single-piece unit. This type of repair work is messy, costly, and time-consuming. For these reasons, tubs and showers are preferably constructed so that the surrounding wall framing and insulation remain dry.
Until relatively recently, shower stalls, bathtubs and sinks were fabricated from ceramic tile, cast iron covered with porcelain, or steel covered with porcelain. With the use of ceramic tile, a lead or rubber liner, called a "pan," was laid within an enclosure where the tub or shower was to be situated. The soft lead or rubber was folded up against the 2'.times.4' wall studs of the enclosure. With the pan material attached to the wall studs, concrete was poured with an opening left for a drain, and then the tile was laid in place. The pan was intended as a secondary seal to prevent water from leaking into the surrounding wall structure. With regard to cast iron or steel tub constructions, the primary seal against water was formed by applying caulking between the tub and the base of the surrounding tile. A cast raised bead or nailing flange is incorporated in many tubs to provide a secondary seal. Presently, a variety of plastics are a modern alternative to the tile and cast iron structures of the past. Surfacing materials include fiberglass, marble, fiber-reinforced plastic, and Surell.RTM. (a densified polyester resin-based material available from Formica Corp.). Plastics are more economically molded than steel or iron. In addition, plastics are lighter in weight, more flexible and more durable.
Some plastic tubs and shower bases are constructed so as to include an integral water seal. Particularly, the base structure of the tub or shower has an upstanding rigid flange along its perimeter. The rigid flange may be attached by a screw or nail to the wall studs. In turn, the wall panels that form the walls of the shower or tub are hung around the perimeter of the base structure of the tub or shower. Typically, the bottom edge of the wall panels are spaced a short distance from the tub or shower base unit. Caulking therefore is required to effectively seal the bottom edge of the wall panels. The caulking is the primary barrier to water and the upstanding rigid flange is the secondary barrier.
While effective at preventing water from leaking into the wall framing, tub and shower bases with integral water seals fixed in size. They cannot be used for custom or retrofit applications. Custom and retrofit applications require more flexible sizing where the base can be cut or trimmed to fit the desired enclosure.
Further, tub and shower base structures having an integral seal often require adjustment to fit into even standard size unfinished enclosures. In order to fasten the rigid flange to the wall studs, the integral seal tub or shower base structure must be pre-drilled and, sometimes, requires shims to adjust for variation in size and level. Pre-drilling and shims are needed to prevent the rigid flange from cracking or bending during installation.
The rigid flange likewise may crack or become crazed if improperly handled. For example, if an installer accidentally steps on the rigid flange, it could crack. Because rigid flanges are fragile, such tubs and shower bases require additional protection in packaging and handling.
In view of the above, there remains a need for a device and method of providing a secondary water seal in the event that the primary water seal between the surrounding wall panel and the base structure of the tub or shower fails. Further, there remains a need for a secondary seal that can be used with tub and shower base structures and allows for trimming or cutting at the installation site in order to fit into an enclosure. Additionally, the secondary seal must be attachable to the wall frame without cracking or bending and must be sturdy for handling and shipping purposes.